Hair rollers of various types are commonly used to create permanent or temporary waves in hair. The hair on the rollers may be either wet or dry; and the rollers may be heated, internally or externally, or not at all. For permanent waves the hair is wetted with a solution or lotion which alters the molecular structure of the hair. For temporary waves, the hair may be dry, or may be wetted with water or with a lotion which produces a surface coating on the hair.
Prior to the instant invention, there was no single roller type which was capable of being used effectively for all of the above applications.
One common use of hair rollers is in heat-assisted waving in which the roller is preheated before hair is wound around it and in which the roller transmits its heat to the hair to effect or to assist in the effecting of the desired wave.
Hair rollers in use today for heat-assisted waving are usually essentially cylindrical with external tongues, or fins, extending at right angles to the cylindrical surface so that the fins can catch a strand of hair at the start of the winding process and thereby facilitate the winding. An example of this type of hair winder is U.S. Pat. No. 3,706,315 to Johansen. It is a disadvantage of the fins, or tongues, that they leave marks on the finished hair coiffure.
Other hair rollers have been devised which have outer pads that are porous and compressible and which do not include fins or tongues. For example, U.S. Pat. No. 3,200,826 to Solomon discloses a hair roller having a porous material of sponge-like form, such as foam rubber, polyurethane sponge, or other synthetic, or resinous, or plastic sponge. U.S. Pat. No. 3,759,271 to Caruso discloses an outer pad that is preferably a foam polymeric plastic, such as foam polystyrene or foam polyurethane.
The hair rollers described by both of the aforementioned patents are disadvantageous for heat-assisted waving because a foam covered roller has insufficient mass for holding an adequate amount of heat for maximum effectiveness in waving the hair. Also, a foam material, when dry, will wick waving solution away from the hair, resulting in uneven distribution of solution on the hair. Conversely, if the foam material is saturated with solution, more solution than is needed would be used on the hair, which is wasteful. Furthermore, the Caruso patent requires a porous pad material since the steam must pass through the porous pad in order to contact the hair.
Hair rollers have also been used to form permanent waves in the hair without using added heat ("cold waving"). The hair is wrapped on conventional rods that have a relatively small diameter so that springiness will be imparted to the hair. Rubber bands are used to retain the hair on the rods. Permanent waving lotion is applied to the hair, allowed to change the molecular structure of the hair, then neutralized, rinsed and rewrapped on to larger rollers. The hair dries while wrapped on the larger rollers either in ambient air or under a heating device, such as a hair dryer or heat lamp.
There are several disadvantages to using conventional permanent wave rods in cold waving. The hair cannot be dried on the relatively small diameter rollers because the rubber bands would leave marks, in the form of identations, on the hair. The hair cannot be wrapped on large diameter hair rollers initially because a smaller diameter is preferred for the purpose of imparting more springiness to the hair, and because large diameter hair rollers and their associated fasteners, prior to this invention, generally were not impervious to the waving lotion that is applied to the hair. Still another disadvantage of using conventional permanent wave rods is that the wrapping of small diameter rods is generally ineffective with long hair in excess of shoulder length, so that it can be used only by persons with relatively short hair.
Prior to the present invention hair rollers, or curlers have been disclosed which use a resilient material for the body of the hairs roller, such as U.S. Pat. No. 2,218,082 to Caldora and U.S. Pat. No. 2,179,525 to Solomon. The resiliency of the material in the Caldora hair curler is for the purpose of enabling a clamp to be forced over ribs in the reduced diameter portion of the mandrel and is therefore sufficient only to permit inward deflection of the ribs. Likewise, the material used in the curler disclosed in the Solomon patent is flexible so that a pair of lips at one end of the roller can be separated from one another and subsequently closed about the hair holding slot in the curler.